Getter



Sept. ,21, 1948.` l G. H. LQcKwooD ETAI. 2,449-785 GETTER Filed March5....1943.

BY Mm ATTORNEY Patented Sept. 21, 1948 STATES PATENT OFFICE Corporation,East Pittsburgh, Pa, a crporation of Pennsylvania Application March 5,1943, Sel No. 478,116

s claim. (ci. 31e-25) This invention relates to incandescent electriclamps and similar evacuated or hermetlcally sealed devices, and moreparticularly, to a getter suitable for the purpose.

The primary object of our invention, generally considered, is the use ofa. material having a strong afilnity for carbon monoxide and oxygen, andforming non-volatile porous compounds therewith, for cleaning-upundesired residual gases in hermetically sealed devices such as in-Acandescent electric lamps and the like.

Another object of our invention is to employ a getter in incandescentelectric lamps and similar devices which avoids filament embrittlementand the formation of an impervious coating, whereby it is completelyavailable for clean-up purposes.

A further object of our invention is the employment .of a getterconsisting essentially of powdered free metallic zirconium, thorium,cerlum or the like, particularly adapted for incandescent electric lampsand similar evacuated devices using nlekel-plated iron and nickel leads,which is especially adapted for cleaning-up such undesired residualgases as carbon monoxide and oxygen, thereby improving the operation andmaintenance of such devices. Carbon monoxide is especially undesirablewith nickel and iron because of the formation of volatile carbonylcompounds therewith.

A still further object of our invention is `the employment of a getter,such as described in the preceding paragraph, in combination withiinelydivided or powdered aluminum or other similar material whichserves the multiple purpose as a binder for the getter metal powder, formaking the mixture more visible when applied to an interior lead of thedevice, and for providing additional getter action.

Other objects and advantages of the invention will become apparent asthe description proceeds.

Referring to the drawing:

Figure 1 is an axial sectional view, with parts in elevation, of a lampembodying our invention.

Figure 2 is a transverse sectional view on the line II-lI of Figure 1.

With the increasing shortage of such strategic materials as copper andnickel due to war conditions, manufacturers have found it expedient to Yresort to the use of nickel-plated iron leads for incandescent electriclamps and similar evacuated or inert gas-filled devices. With such leadsas well as nickel leads, particularly due to the desirability ofannealing in order to clean and soften them, which annealing alsousually took place in a carbon-monoxide-containing atmosphere, it hasbeen found that getters such as previously used are unsatisfactory dueto an embrittling action on the -tllament of the residualcarbon-monoxide which was not entirely cleaned up.

In searching for an eiective clean-up agent for carbon monoxide, as suchgas is particularly bad because of its cycle with nickel and iron due toits formation of vaporizable carbonyl compounds with such materials, itwas found that a getter consisting essentially of at least one of thepowdered metals such as zirconium, thorium and cerium, having a strongaffinity for carbon monoxide and oxygen, forming non-'volatile butporous compounds therewith, in combination with fine degreased aluminumakes, that is, not including other ingredients except minor impurities,is particularly suitable when applied, as by means of a. harmlessvehicle such as amyl acetate, by painting on lead and/or support wiresin miniature and large incandescentillament lamps.

The rare metals mentioned are considered the most active ingredients forthe desired clean-up purpose, but the flake aluminum ls desirablyemployed therewith to perform the multiple function as an auxiliarygetter material, a binder for the other metal powder, and as avisibility-increasing agent. It will be understood that zirconium metalpowder, for example, is dark grey in color and, therefore, would not bevery visible if it alone were mixed with amyl acetate and painted on a.lead-in conductor or other non-incandescing portion. With a suitableminor proportion of aluminum, however, it shows up clearly in the sameway in which aluminum paint would and is more firmly held in place bysuch auxiliary material.

The proportions of the lngredlentswhich have been found suitable for thepurpose are as follows:

Zirconium metal powder, 325 mesh grams 18 Degreased aluminum ake, 400mesh do 4 Amy] acetate cc-.. 40

The above formula is now in use in the factory production of lamps andhas given good results.

In the drawing, the reference character I0 denotes an incandescentelectric lamp comprising an envelope Ii based as indicated at I2, andenclosing a are tube I3.` From the tube i3l extends lead-in conductorsIl and I5 to an incandescible lament I6, secured to an arbor i1 by oneor more support wires Il;

In the .present embodiment, the lead wires Il and I5 and the supportingwire, or wires, Il are shown coated with a paint I9 comprising theldesired getter mixture in a vehicle such as amyl acetate. Although inthe present embodiment, all of these parts numbered Il, I 5 and Il, areshown with the getter material thereon, it will be understood that suchmaterial may if desired be applic to only some of these parts.

From the foregoing disclosure it will be seen that we have developed animproved getter'particularly adapted for use on nickel-plated iron andnickel leads and supports in incandescent electric lamps, whethergas-lled or vacuum type. It consists essentially of a major proportionof material such as powdered zirconium, thorium, cerlum, that is, atleast one oi' said 'powdered metals or other similar material having astrong ainity for carbon monoxide and oxygen, forming non-volatile andporous compounds therewith and which has no embrittling eect on theillament, while at the same time being sufllciently active at relativelylow temperatures to operate when applied to a lead or support in theenvelope, as distinguished from the application to an incandesciblefilament and a minor proportion of ilnely divided aluminum.

Although preferred embodiments of our invention have been described. itwill be understood that modiiications may be made within the spirit andscope of the appended claims. It will,`how ever, be understood thatthere is no intention to include unmentioned ingredients other thanminor impurities.

We claim:

1. A getter for incandescent velectric lamps consisting essentially of amajor proportion of at least one free powdered metal selected from thegroup consisting of zirconium, thorium, and cerium, admixed with a minorproportion of degreased aluminum ilake to act as a binding and auxiliaryclean-up agent.

2. A getter for incandescent electric lamps consisting essentially of amajor proportion of zirconium metal powder, admixed with a minorproportion of degreasedv aluminum flake to act as a bindingagent andauxiliary clean-up agent. 3. A getter composed of ingredients admixedvin about the following proportions: zirconium metal powder, 325 mesh,18 grams; aluminum flake-400 mesh, 4 grams; and amyl acetate, cc. f

4. A getter for incandescent electric lamps consisting essentially of amajor proportion of thorium metal powder, admixed with a minorproportion of degreased aluminum iiake to act as a binding and auxiliaryclean-up agent.

5. A getter for incandescent electric lamps 4 comprising essentially amajor proportion o1' cerium metal powder, admixed with a minorproportion of degreased aluminum ake to act as a binding and auxiliaryclean-up agent.

6. A getter for residual gases in hermetically sealed envelopescomprising a coating on an ele.

ment therein which inservice becomes hot without incandescing,consisting o! ingredients admixed in about the following proportions:zirconium metal powder, 325 mesh, 18 grams; aluminum ilake, 400 mesh, 4grams; and amyl acetate, 40 cc.

7. A getter for incandescent electric lamps comprising a coating on aninterior lead portion thereof consisting essentially of a majorproportionl of at least one powdered free metal selected from the groupconsisting of zirconium, thorium and cerlum admixed with a minorproportion of degreased aluminum iiake. l

8. A getter for residual gases in hermetically sealed envelopescomprising a coating, on an element therein which in service becomes hotwithout incandescing, consisting'essentially o! a major proportion of atleast one free powdered metal selected from'the group consisting oizirconium, thorium and cerium. admixed with a minor proportion offinely-divided aluminum.

GEORGE H. LOCKWOOD. DONALD F. WAY.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 286,916 Fitzgerald v.. Oct. 16,1883 1,323,836 Coolidge Dec. 2, 1919 1,560,981 De Graaff Nov. 10, 19251,590,352 Eglin June 29, 1926 1,626,235 Gustin Apr. 26, 1927 1,653,367Marden Dec. 20, 1927 1,691,177- Balke Nov. 13, 1928 1,859,029 De Br etal May 17, 1932 1,859,043 Maartens May 17, 1932 1,864,084 Miller June21, 1932 1,894,948 Espe et al Jan. 24, 1933 1,922,162 King s Aug. 15,1933 1,967,575 Hunter, Jr. July 24, 1934 2,117,735 Lester May 17, 19382,295,694 Slack et al. Sept. 15, 1942 2,341,483. Stephen A.' Feb. 8,1944 A FOREIGN PATENTS Number v CountryA Date 107,314 Australia May 11,1939 482,022, Great Britain Mar. 22, 1938

